Water-disintegratable papers or cleaning goods made of a chemical-containing water-disintegratable paper which can be thrown into water have been used as toilet paper or for cleaning a toilet room or toilet equipment. Conventional water-disintegratable paper usually contains a dry strength agent such as polyvinyl alcohol, carboxymethyl cellulose, and cationic starch, for enhancing dry paper strength without impairing water disintegrability.
However, a paper sheet containing a dry strength agent undergoes serious reduction of strength when impregnated with water. Therefore, where a water-disintegratable paper is combined with a cleaning agent for cleaning or sterilization of floors, walls, furniture, and toilet equipment or for use as toilet paper, the cleaning agent to be combined therewith has been limited to liquid substances or chemicals having no or very low water content.
In using a cleaning agent of high water content, it has been necessary that the cleaning agent should be foamed and sprayed on a water-disintegratable paper immediately before use and be used without delay in order to suppress water absorption into paper and to prevent strength reduction.
Polyacrylamide or the like, as a dry strength agent endows paper with strength enough to withstand use even with a small amount of water being impregnated in the paper sheet, but tends to impair water disintegratability of the sheet.
Hence, the conventional dry strength agents could not provide a strength enough to withstand cleaning use even when combined with a cleaning agent of high water content in good balance with water disintegratability.
It has been proposed to spray a binder solution containing polyvinyl alcohol and borax on a paper sheet followed by drying by heat whereby polyvinyl alcohol and borax are reacted to provide water-disintegratable paper having temporary water resistance, which is useful as absorbent materials such as napkin or diaper, as disclosed in JP-A-47-9486 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). Further, JP-A-61-296159 discloses a water-disintegratable paper in which an aqueous solution containing salts such as potassium salt, calcium salt and barium salt, is impregnated into a fibrous sheet containing carrageenan as a binder, which is used for a wetting tissue paper. Furthermore, JP-A-55-103393 discloses a method for preparing a paper having high strength in a dry state while low in wet state, which comprises treating paper surface with alkali metal and/or alkali earth metal salt of polyacrylic acid polymers, and that the paper can be used for writing paper, printing paper, wrapping paper, etc. These water-disintegratable papers, however, do not withstand the mechanical force in cleaning work when impregnated with water.